In recent years, some limited attempts have been made to apply software PID control to control computer data network traffic. Consistent with the historical application of hardware PID controllers, these applications have focused on stabilizing traffic to avoid highly fluctuating data transmission rates.
Aweya, et al., in “Rate-based proportional-integral control scheme for active queue management”, International Journal of Network Management, March 2006, present a two-term Proportional-Integral (PI) control algorithm that enables rate-based Active Queue Management (AQM) schemes to “match the aggregate rate of the active TCP connections to the available capacity while maintaining minimal queue size and high link utilization”.
Hong, et al., in “Design of Adaptive PI Rate Controller for Best-Effort Traffic in the Internet Based on Phase Margin”, IEEE Press, April 2007, proposed a PI rate controller to provide best-effort traffic in the Internet. This AQM control system aims to improve transient behavior by adapting to sudden changes in the network environment.
Li Yu, et al., in “An Analysis and Implementation Study on a Robust Congestion Controller for the Internet”, International Conference on Advanced Infocomm Technology, Jul. 29-31, 2008, Shenzhen, China, describe a PID controller for Internet congestion control, the main advance being its robustness in adapting to dynamic networks.
In contrast, an important goal of the present invention is to maximize the data transmission rate within available bandwidth limits, i.e. to transmit datagrams as rapidly as possible while avoiding unacceptable amounts of datagram losses or corruption under changing network conditions.